Troubleshooting an e-bike kit that stopped working

[hsors]

The e-bike kit that I mounted on my bike has been working fine for two weeks (220km). Today when I started up I heard strange vibrations and noise that disappeared as I increased speed. Then I slowed down, vibrations came up again. I stopped and couldn't resume. The motor wouldn't spin. Then I pedaled manually and suddenly after a few minutes the motor went on again, with the same vibrations and noise that disappear with speed. Again when I stopped I couldn't resume and again when I had pedaled for a few minutes the motor went on again but would not resume after a stop.
Any idea on what could be the problem and if not how to diagnose it ? The motor is probably not out of work because it goes on from time to time. But what about the hall sensors ? Another obvious culprit could be the controller but it's hard to understand the intermittence of the phenomena.
Configuration:
- BMS battery S12S 500W controller with a S-LCD1 display
- Bafang BPM 500W/48V motor (201rpm)
- 48V10Ah LiFePO4 Alloy 03-CASE EBike Battery
Thanks for any clue !

 

[Zone Seeker]

Perhaps the vibrations could be caused by a faulty bearing or crunched gears that makes the motor struggle a lot more than usual?

 

[Ykick]

here's one of those links to always keep handy - http://www.ebikes.ca/learn/troubleshooting.html

If/when it runs rough does your display read Amps? With the wheel off the ground when the motor spins jerky/rough - high Amp draw indicates a loss of timing with regard to Power Phase windings and Hall Sensor signals.

Troubleshooting link will have Hall sensor testing info - in your case the geared hub motor will need to be spun backwards in order to engage the motor to the wheel.

Check all the primary motor/controller connections - particularly look for contacts that sometimes back out of the connector housing.

Another area to qualify may be your battery performance but check all the above 1st.

Good luck

 

[arkmundi]

here's one of those links to always keep handy -http://www.ebikes.ca/learn/troubleshooting.html

Yea, nice link. But in this circumstance, since its 2 weeks out of the box, what I'd do is pack it up in that box and send it back to the supplier claiming warranty repair and let the folks on the other end work out what happened, what works or not, fix it and send it back in good working order.

That said, its necessary for us eBike wonks to have a troubleshooting third sense, as its inevitable that components will fail, and we all want to get back on the saddle as quickly as possible. My own recent experience was in a throttle fail. But before knowing that and getting a replacement, it was, geeze, what's wrong? Could'a been the controller, or the wiring, or the thermister in the motor, or any one of several dozen wire connections. All I knew was, it was not the battery, which is easy to check and was working great. It was some troubleshooting that improved my confidence that it was the throttle to more that 50%.

 

[Ykick]

Yea, nice link. But in this circumstance, since its 2 weeks out of the box, what I'd do is pack it up in that box and send it back to the supplier claiming warranty repair and let the folks on the other end work out what happened, what works or not, fix it and send it back in good working order.

That said, its necessary for us eBike wonks to have a troubleshooting third sense, as its inevitable that components will fail, and we all want to get back on the saddle as quickly as possible. My own recent experience was in a throttle fail. But before knowing that and getting a replacement, it was, geeze, what's wrong? Could'a been the controller, or the wiring, or the thermister in the motor, or any one of several dozen wire connections. All I knew was, it was not the battery, which is easy to check and was working great. It was some troubleshooting that improved my confidence that it was the throttle to more that 50%.

In a perfect world, certainly. Unfortunately, eBike supplies don't yet exist in a perfect world. The cost(s) to ship this stuff around will legally be born by the consumer. Much like a TV bought from Walmart, they'll warranty it but you still have to haul it back to the store. They'ain't gonna send a driver to your home on their Dime and haul it back to the store for you....

Also, any seller can point to this as "custom installation(s)" and who can assign what's under warranty or merely operator/installer error? So, until there's a Grin Cyclery in every metro neighborhood we're left sharing tidbits of technical knowledge as best we can.

 

[dnmun]

sounds like a loose connection on the phase or battery leads. no pictures, no examination by the OP yet so wait until he does something to determine the problem before offering answers. otherwise he won't look, but will think that the multiple answers somehow might work.

so if you can post up pictures so we know what you have, and what the currents were before and during these bad spots we can try to help you figure it out.

 

[hsors]

Thanks for the hints.
BMSbattery offers to ship a free controller but they said they can ship the S12P (for sensor less motors) whereas I need a S12S for a sensor motor (Bafang BPM). Still talking to them to try to understand what's behind...
To Dnmun: thanks for the offer for help. Not sure at this point how photos would help diagnose as there is no external sign of the failure. My post was mainly to understand if this problem was a classic one with an easy to identify failing component. Apparently not.
Will continue to investigate and post an update.

 

[dnmun]

pictures help us know what you have. how you can get correct advice without anyone knowing what it is they are talking about is beyond me. but they will give you all the advice you need anyway.